• • One has a good distance: 2021rhu (ZTF21abiuvdk). NGC7814. This has a measured distance of 30.84 mag.

• Adam M, Alice T, Ana S-C, Ariel G, Bastien C, Benjamin R, Estelle R, Georgios D, Jacco T, Jakob N, Jeremy L, Joel J, Kelian S, Leander L, Luke H, Melissa A, Mickael R, Mat S, Nicolas R, Nora N, Philippe R, Simeon R, Suhail D, Valery B

• Golden opportunity to get your favourite target observed with SEDm.
  • Jeremy L is targeting host galaxies to test hypergal. What else can we do? Track thnigs on #slack

• It's clear that there are lots of parallel efforts going on across the WG and in other WG's. Let's combine efforts and work together
• An obvious example is the photometry: there are multiple codes (FPbot; IPAC FP; ...) that do the same thing.
  • As a result there is now a 'photometry-taskforce' of interested participants spanning SNIa and BTS. Jakob N is coordinating this.
  • The main differences lie in the cuts and baseline correction: the aim is to determine a unified code for everyone to work from.
• (See Mickael's flow-chart for an idea of how the WG is interconnected).
• The plan is to have several sub-working groups (simulations, light-curves, spectra, hosts, weirdos, ...) that we hope will meet independently and then report every week.
  • Everything must be documented; where should we do it? (slack?); what papers are being written?
  • We'll create the #wg-XXXX channels today and encourage people to join. Each WG should have a convenor.

• This is a proof of concept atudy using a nearby ZTF SN: eventually the plan is to do it with a sample: with one sample across redshifts we can take out calibration issues.
• TRGB is an alternate way to measure distances in the local universe; it's independent of galaxy type, and does not suffer from metallicity / crowding issues.
• The base sample is anything less than 20Mpc (4 events). These are HST'able. There are 50 to 80Mpc: these are JWST'able.
  • One has a good distance: 2021rhu (ZTF21abiuvdk). NGC7814. This has a measured distance of 32.84 mag.
  • Suhail has written a MCMC code to infer H0. The current uncertainty is 8%: it's dominated by the local measurements.
  • A draft ApJ letter is being written: want it submitted prior to the HST deadline (April 2022).
• A draft will be circulated this week. The value is blinded; will be unblinded prior to submission.

• Just a quick update on the status of the DR2 host galaxy analysis. We have 2600 cosmological SN; 920 with a spec_z.
• In terms of completeness, the sample appears to be volume limited to z=0.05, which equates to 540 SNe, 300 of which have a spec_z.
• In terms of the populations, there is an excellent agreement between the x1 distribution and the Nicolas 2021 model both for ZTF and at high-z.
• In terms of hosts; Mat has automated host matching, and estimated masses, sSFR and local measurements for all SNe.
• There is a strong correlation between x1 and mass: more on this to follow next week.
• (See the attached slides for details).

• Melissa is working on simulating ZTF.
• She's looking to validate simsurvey: taken known SN, and seeing what happens if we try to replicate them.
• It works: the fluxes are correct; the errors are slightly under-estimated. This needs to be

• The first production run of hypergal is underway.
• There are 2087 targets in the DR2 sample. 1200 have already been run through hypergal: 86% pass.
• The results are automatically being pushed to a slack.
• The entire sample should be run by the end of the week. The results are in a GoogleDrive folder.
• This will be shared with the WG today.
• Joel: we should run this on everything, especially the untyped spectra. Ariel: there are 10-20% of spectra that are untyped; this could do loads.

ZTF Ia Phone-con: 2021-Dec-01

Meeting Agenda:

1. SNe of the week [Joel J]

2. Organising the SNIa WG [Mickael R]

3. TRGB+ZTF: H0 [Suhail D]

4. Host Galaxy Updates [Mat S]

5. Simulating ZTF [Melissa A]

6. HyperGal Status [Jeremy L]

7. AOB / Close

-

Participants (XX):

• Apologies:

Transients of the Week:

• ZTF has been down all week, so nothing ;(

Organising the Working group (Mickael R):

TRGB / ZTF H0 Update (Suhail D):

Host Galaxy / DR2 Sample updates (Mat S):

Simulating ZTF (Melissa A):

HyperGal Updates (Jeremy L):

Closing remarks:

• Back next week